When I want to get directions between two well-known places, I enter a query like "from Heaven to Hell" into Google, then switch to Maps tab and the route is there (provided that Heaven and Hell are known locations by Google; exact addresses qualified with city name work too). But it shows the default path, using the car. Is there a way to write the query that will yield a walking path?

Doesn't look like it. Walking directions are in beta (as they always remind you) and based on my tests they simply take what's before "to" as the origin and the text after as the destination. Nothing I tried would get it to start with the walking directions.
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Al E.Jan 3 '13 at 14:19